Semiconductor device structures inlcuding a distributed bragg reflector

ABSTRACT

A method of forming a semiconductor device structure comprises forming at least one reflective structure comprising at least two dielectric materials having different refractive indices over at least one radiation-sensitive structure, the at least one reflective structure configured to substantially reflect therefrom radiation within a predetermined wavelength range and to substantially transmit therethrough radiation within a different predetermined wavelength range. Additional methods of forming a semiconductor device structure are described. Semiconductor device structures are also described.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a divisional of U.S. patent application Ser. No.13/590,928, filed Aug. 21, 2012, pending, the disclosure of which ishereby incorporated herein in its entirety by this reference.

TECHNICAL FIELD

Embodiments of the disclosure relate to the field of semiconductordevice design and fabrication. More specifically, embodiments of thepresent disclosure relate to methods of forming semiconductor devicestructures, and to related semiconductor device structures.

BACKGROUND

Plasma treatment processes, such as plasma etching or depositionprocesses, are frequently used during the fabrication of semiconductordevices for integrated circuits. For example, during the fabrication ofcomplementary metal oxide semiconductor (CMOS) devices, plasma etchingprocesses can be used after CMOS transistor formation to produce one ormore structures (e.g., contacts, bond pads, trenches, etc.). However,plasma treatment processes produce wavelengths of radiation that cannegatively affect CMOS device performance, reliability, and durability.For instance, exposure to certain wavelengths of produced ultravioletradiation may result in one or more of defects, impurities, and brokenchemical bonds in CMOS transistors.

Conventional methods of reducing defects, impurities, and brokenchemical bonds resulting from exposing radiation-sensitive structures(e.g., CMOS transistors) to ultraviolet radiation include forming atleast one radiation-absorbing material (e.g., an anti-reflectivecoating) over the radiation-sensitive structures. Unfortunately, theefficacy of the radiation-absorbing material is largely dependent on thethickness of the radiation-absorbing material. For example, thickerradiation-absorbing materials are typically required to impede radiationtransmittance at higher radiation intensities, resulting in increasedmaterial expense and the formation of larger semiconductor devicestructures. In addition, the radiation-absorbing material candisadvantageously limit or prevent the use of various photolithographicprocesses (e.g., those utilizing lower wavelengths of radiation, such aswavelengths less than or equal to about 193 nanometers) in the formationof semiconductor device structures.

A need, therefore, exists for simple and cost-efficient methods to atleast reduce, if not eliminate, at least the aforementioned problems.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIGS. 1A and 1B are cross-sectional views illustrating different processstages and structures for a method of forming a semiconductor devicestructure in accordance with embodiments of the disclosure;

FIG. 2 is a cross-sectional view of a semiconductor device structure inaccordance with embodiments of the disclosure;

FIG. 3 is a cross-sectional view of another semiconductor devicestructure in accordance with embodiments of the disclosure; and

FIG. 4 is a cross-sectional view of yet another semiconductor devicestructure in accordance with embodiments of the disclosure.

DETAILED DESCRIPTION

Methods of forming semiconductor device structures are disclosed, as arerelated semiconductor device structures. In some embodiments, a methodof forming a semiconductor device structure includes forming at leastone reflective structure on or over at least one structure or material,such as at least one radiation-sensitive structure. As used herein, theterm “radiation” means and includes all types of electromagneticradiation, including ultraviolet (UV) radiation. As used herein, theterm “radiation-sensitive structure” refers to a structure or materialexhibiting undesired chemical bond breakage (e.g., covalent bondbreakage), defect activation, and/or impurity formation upon exposure toat least some wavelengths of radiation. The at least one reflectivestructure may include at least two dielectric materials having differentrefractive indices, and may be formed to exhibit a desired reflectivityand to selectively reflect radiation within a predetermined wavelengthrange. The presence of the at least one reflective structure on thesemiconductor device structure may at least partially protect theradiation-sensitive structure from detrimental exposure to radiationproduced in association with subsequent processing of the semiconductordevice structure, which may improve semiconductor device reliability,performance, and durability.

The following description provides specific details, such as materialtypes, material thicknesses, and processing conditions in order toprovide a thorough description of embodiments of the disclosure.However, a person of ordinary skill in the art will understand that theembodiments of the disclosure may be practiced without employing thesespecific details. Indeed, the embodiments of the disclosure may bepracticed in conjunction with conventional fabrication techniquesemployed in the industry. In addition, the description provided hereindoes not form a complete process flow for forming a semiconductor devicestructure, and the semiconductor device structures described below donot form a complete semiconductor device. Only those process acts andstructures necessary to understand the embodiments of the disclosure aredescribed in detail below. Additional acts to form the completesemiconductor device may be performed by conventional fabricationtechniques. Also note, any drawings accompanying the application are forillustrative purposes only, and are thus not drawn to scale.Additionally, elements common between figures may retain the samenumerical designation.

As used herein, relational terms, such as “first,” “second,” “top,”“bottom,” “upper,” “lower,” “over,” “under,” etc., are used for clarityand convenience in understanding the disclosure and accompanyingdrawings and do not connote or depend on any specific preference,orientation, or order, except where the context clearly indicatesotherwise.

As used herein, the term “substantially,” in reference to a givenparameter, property, or condition, means to a degree that one skilled inthe art would understand that the given parameter, property, orcondition is met with a small degree of variance, such as withinacceptable manufacturing tolerances.

As used herein, the term “substrate” means and includes a base materialor construction upon which additional materials are formed. Thesubstrate may be a semiconductor substrate, a base semiconductor layeron a supporting structure, a metal electrode or a semiconductorsubstrate having one or more layers, structures or regions formedthereon. The substrate may be a conventional silicon substrate, or otherbulk substrate comprising a layer of semiconductive material. As usedherein, the term “bulk substrate” means and includes not only siliconwafers, but also silicon-on-insulator (SOI) substrates, such assilicon-on-sapphire (SOS) substrates and silicon-on-glass (SOG)substrates, epitaxial layers of silicon on a base semiconductorfoundation, and other semiconductor or optoelectronic materials, such assilicon-germanium, germanium, gallium arsenide, gallium nitride, andindium phosphide. The substrate may be doped or undoped.

FIGS. 1A and 1B, are simplified partial cross-sectional viewsillustrating embodiments of a method of forming a semiconductor devicestructure that includes forming at least one reflective structure on orover at least one radiation-sensitive structure. The reflectivestructure may reduce damage and performance degradation resulting fromexposing the radiation-sensitive structure (e.g., a transistor) toradiation within a particular wavelength range. With the description asprovided below, it will be readily apparent to one of ordinary skill inthe art that the methods described herein may be used in variousapplications. In other words, the methods of the disclosure may be usedwhenever it is desired to reflect radiation within a particular range ofwavelengths during the formation of a semiconductor device structure.

Referring to FIG. 1A, a semiconductor device structure 100 may include asubstrate 102 and at least one radiation-sensitive structure 104. Theradiation-sensitive structure 104 may be located in, on, or over thesubstrate 102. By way of non-limiting example, as depicted in FIG. 1A,the radiation-sensitive structure 104 may be a transistor, such as aCMOS transistor, including source and drain regions 106 a, 106 b formedin the substrate 102, a channel region 108 formed between the source anddrain regions 106 a, 106 b, and a gate structure 110 formed on or overthe channel region 108 and at least partially surrounded (e.g.,laterally surrounded) by an electrically insulative material 120. Thegate structure 110 may include, for example, a gate oxide 112 formed onor over the channel region 108, a first conductive material 114 (e.g., apolysilicon, a polycide, etc.) formed on or over the gate oxide 112, asecond conductive material 116 (e.g., a more conductive material thanthe first conductive material 114, such as a more conductive metalsilicide material) formed on or over the first conductive material 114,and a capping material 118 (e.g., an electrically insulating material,such as a silicon nitride material) formed on or over each of an uppersurface of the second conductive material 116 and sidewalls of the gateoxide 112, the first conductive material 114, and the second conductivematerial 116. Each of the substrate 102 and the radiation-sensitivestructure 104 may be formed using conventional techniques, which are notdescribed in detail herein.

Referring to FIG. 1B, at least one reflective structure 122, which mayalso be referred to as a distributed Bragg reflector (DBR), may beformed on or over at least the radiation-sensitive structure 104. Thereflective structure 122 is formed to include a stack of at least twodielectric materials having different refractive indices. For example,as shown in FIG. 1B, the reflective structure 122 may include adielectric material 122 a formed on or over the gate structure 110 andthe electrically insulative material 120, and another dielectricmaterial 122 b formed on the dielectric material 122 a. The dielectricmaterial 122 a may have a higher refractive index or may have a lowerrefractive index than the another dielectric material 122 b. Thedifferent refractive indices of adjacent dielectric materials of thereflective structure 122 (e.g., the dielectric material 122 a, and theanother dielectric material 122 b) at least partially enable thereflective structure 122 to reflect radiation, as described in furtherdetail below.

The reflective structure 122 may be formed and configured to exhibit adesired reflectivity. For example, for a reflective structure 122including at least one pair of adjacent dielectric materials, areflectivity of the reflective structure 122 may be tailored accordingto the following equation:

$\begin{matrix}{{R = \left\lbrack \frac{{n_{0}\left( n_{2} \right)}^{2N} - {n_{s}\left( n_{1} \right)}^{2N}}{{n_{0}\left( n_{2} \right)}^{2N} + {n_{s\;}\left( n_{1} \right)}^{2N}} \right\rbrack^{2}},} & (1)\end{matrix}$

where R is the reflectivity of the reflective structure 122, n₀ is arefractive index of a material overlying the reflective structure 122,n_(s) is a refractive index of a material underlying the reflectivestructure 122, N is the number of pairs of the adjacent dielectricmaterials in the reflective structure 122, and n₁ and n₂ are therespective refractive indices of the adjacent dielectric materials. Asindicated by Equation 1, increasing at least one of a refractive indexcontrast (i.e., difference in refractive indices between the adjacentdielectric materials) and the number of pairs of the adjacent dielectricmaterials may increase the reflectivity of the reflective structure 122.As a non-limiting example, the reflective structure 122 may reflectgreater than or equal to about 60 percent, such as greater than or equalto about 90 percent, or greater than or equal to about 95 percent, orgreater than or equal to about 99 percent, or greater than or equal toabout 99.5 percent of radiation within a particular wavelength range.

The reflective structure 122 may be formed and configured to reflect abroad range of radiation wavelengths. For example, for a reflectivestructure 122 comprising at least one pair of adjacent dielectricmaterials, a photonic stopband of the reflective structure 122 may betailored according to the following equation:

$\begin{matrix}{{{\Delta \; \lambda_{0}} = {\frac{4\; \lambda_{0}}{\pi}{\arcsin \left( \frac{n_{2} - n_{1}}{n_{2} + n_{1}} \right)}}},} & (2)\end{matrix}$

where Δλ₀ is the photonic stopband, λ₀ is a central wavelength of theband, and n₁ and n₂ are as previously described. As used herein, theterm “photonic stopband” refers to a wavelength range susceptible toreflection by the reflective structure 122. Wavelengths of radiationoutside of the photonic stopband (e.g., below the wavelength range) areable to pass through the reflective structure 122 with substantially noreflection. The reflective structure 122 may be tailored to exhibit adesired photonic stopband. As indicated by equation 2, increasing therefractive index contrast between the adjacent dielectric materials ofthe reflective structure 122 (e.g., the dielectric material 122 a, andthe another dielectric material 122 b) broadens the photonic stopbandΔλ₀. Thus, as depicted in FIG. 1B, the reflective structure 122 may beformed to selectively reflect particular radiation wavelengths,illustrated as dashed line 123, and transmit other radiationwavelengths, illustrated as dashed line 125. By way of non-limitingexample, the reflective structure 122 may be formed to exhibit aphotonic stopband of greater than or equal to about 100 nanometers (nm),such as greater than about 193 nm. In some embodiments, the reflectivestructure 122 may be formed to reflect ultraviolet radiation producedduring plasma treatment processes, such as ultraviolet radiation withina wavelength range of from about 200 nm to about 400 nm, such as fromabout 250 nm to about 400 nm. The reflective structure 122 maysubstantially reflect (i.e., reflect greater than or equal to about 99percent) of radiation within the range of from about 200 nm to about 400nm, and may substantially transmit (i.e., transmit greater than or equalto about 99 percent) of radiation exhibiting a wavelength of less than200 nm. As compared to conventional methods of protecting aradiation-sensitive structure, such as methods utilizing at least oneradiation-absorbing structure (e.g., an anti-reflective coating), themethods of the disclosure may facilitate increased selectivity forlonger wavelengths of radiation (e.g., wavelengths greater than or equalto about 200 nm), while still enabling the use of shorter wavelengths ofradiation (e.g., wavelengths less than or equal to about 193 nm) forphotolithographic processes (e.g., photoscanning processes). The methodsof the disclosure may thus facilitate the reflection of wavelengths ofradiation that may otherwise damage the radiation-sensitive structure104, while enabling the transmission of wavelengths of radiation thatmay be beneficial to the processing of the radiation-sensitive structure104.

Accordingly, a method of forming a semiconductor device structurecomprises forming at least one reflective structure comprising at leasttwo dielectric materials having different refractive indices over atleast one radiation-sensitive structure, the at least one reflectivestructure configured to substantially reflect therefrom radiation withina predetermined wavelength range and to substantially transmittherethrough radiation within a different predetermined wavelengthrange.

Furthermore, a semiconductor device structure of the disclosurecomprises at least one structure on a substrate, and a reflectivestructure over the at least one structure and configured to selectivelyreflect greater than or equal to about 60 percent of radiation within awavelength range of from about 200 nm to about 400 nm.

In addition, a method of processing a semiconductor device structureincluding a reflective structure over a radiation-sensitive structurecomprises substantially reflecting UV radiation within a predeterminedwavelength range away from the radiation-sensitive structure with thereflective structure, and substantially transmitting UV radiationoutside of the predetermined wavelength range through the reflectivestructure to the radiation-sensitive structure.

Further, a semiconductor device structure of the disclosure comprises aradiation-sensitive structure, and a reflective structure configured tosubstantially reflect UV radiation within a predetermined wavelengthrange, and to substantially allow transmission of UV radiation outsideof the predetermined wavelength range.

Any combination of dielectric materials may be used to form thereflective structure 122 so long as the combination of materials resultsin a suitable refractive index contrast of the adjacent dielectricmaterials of the reflective structure 122, as previously described. Afirst of the adjacent dielectric materials (e.g., the dielectricmaterial 122 a) may, for example, be formed from silicon dioxide (SiO₂),silicon nitride (Si₃N₄), titanium dioxide (TiO₂), zirconium dioxide(ZrO₂), hafnium dioxide (HfO₂), tantalum oxide (Ta₂O₅), magnesium oxide(MgO), a Group III-V compound, or a Group II-IV compound. In turn, asecond of the adjacent dielectric materials (e.g., the anotherdielectric material 122 b) may, for example, be formed from a differentdielectric material from the list above. By way of non-limiting example,the first of the adjacent dielectric materials may be selected to have arefractive index of greater than or equal to about 1.5, such as greaterthan or equal to about 1.7, or greater than or equal to about 2.0, andthe second of the adjacent dielectric materials may be selected to havea refractive index of less than or equal to about 2.0, such as less thanor equal to about 1.5, or less than or equal to about 1.4. In someembodiments, the first of the adjacent dielectric materials is Si₃N₄,which has a refractive index of 2.0, and the second of the adjacentdielectric materials is SiO₂, which has a refractive index of 1.48.

Each dielectric material of the reflective structure 122 may be formedat any suitable thickness. The thickness of each of the dielectricmaterials may at least partially depend on the radiation wavelengthsdesired to be reflected and on a desired reflectivity of the reflectivestructure 122. The thickness of each of the dielectric materials may,for example, be tailored to increase the reflection of a particularradiation wavelength or radiation wavelength range. As a non-limitingexample, for normal incidence, the thickness of each of the dielectricmaterials may be a quarter of a particular radiation wavelength desiredto be reflected (e.g., for a center radiation wavelength of about 200nm, each of the dielectric materials may have a thickness of about 500Angstroms). If the thickness of each of the dielectric materials isabout one quarter of the particular radiation wavelength, the reflectivestructure 122 may reflect substantially all radiation having theparticular wavelength. If radiation incident with angle, the thicknessof each of the dielectric materials may be increased accordingly. Insome embodiments, each dielectric material of the reflective structureis formed to have a thickness greater than or equal to about 500Angstroms (Å). The thickness of each of the dielectric materials (e.g.,the dielectric material 122 a and the another dielectric material 122 b)of the reflective structure 122 may be the same, or at least one of thedielectric materials may have a different thickness than at least oneother of the dielectric materials. In addition, the thickness of each ofthe dielectric materials may be selected independent of radiationintensity considerations. As used herein, the term “radiation intensity”refers to the amount of radiation present in or passing through a givenvolume per unit of time. Conventional methods of protecting aradiation-sensitive structure from radiation, such as methods utilizingat least one radiation-absorbing structure (e.g., at least oneanti-reflective coating), typically require forming thickerradiation-blocking material(s) to sufficiently protect theradiation-sensitive structure at increased radiation intensities. Suchconventional methods may thus disadvantageously result in increasedmaterial requirements and larger structural dimensions. Conversely,using the methods of the present disclosure, as long as the reflectivestructure 122 exhibits a sufficient refractive index contrast and thenumber of adjacent dielectric materials to facilitate a desiredreflectivity, each dielectric material of the reflective structure 122may be formed at a thickness irrespective of radiation intensity.

The dielectric materials of the reflective structure 122 may be formedusing conventional processes, such as physical vapor deposition (“PVD”),chemical vapor deposition (“CVD”), or atomic layer deposition (“ALD”).PVD includes, but is not limited to, sputtering, evaporation, or ionizedPVD. Such deposition processes are known in the art and, therefore, arenot described in detail herein.

After forming the reflective structure 122 on or over theradiation-sensitive structure 104, the semiconductor device structure100 may be subjected to additional processing to form a semiconductordevice that includes the semiconductor device structure 100. By way ofnon-limiting example, additional materials may be formed on thesemiconductor device structure 100 or at least a portion of anadditional material on the semiconductor device structure 100 may beremoved. By way of non-limiting example, the semiconductor devicestructure 100 may be subjected to at least one plasma treatment process,including, but not limited to, one or more of a plasma enhanced chemicalvapor deposition process (PECVD), a plasma etching process, and a plasmacleaning process. The plasma treatment process may produce ultravioletradiation within a wavelength range of from about 200 nm to about 400nm. If the reflective structure 122 were not present, theradiation-sensitive structure 104 would be degraded (e.g., damaged) bythe ultraviolet radiation produced as a result of the plasma treatmentprocess. In some embodiments, after forming the reflective structure122, the semiconductor device structure 100 is subjected to a plasmaetching process. The plasma etching process may, for example, beperformed after the formation of at least one other material (not shown)on or over at least a portion of the reflective structure 122. Theplasma etching process may remove at least a portion of one or more ofthe other material and the reflective structure 122. The reflectivestructure 122 may at least partially reflect the ultraviolet radiation(e.g., ultraviolet radiation within a wavelength range of from about 200nm to about 400 nm) produced during the plasma treatment process to atleast partially protect the radiation-sensitive structure 104 fromexposure to the ultraviolet radiation. Protecting theradiation-sensitive structure 104 from exposure to the ultravioletradiation may reduce or eliminate at least one of radiation-baseddamage, defects, and impurities in the radiation-sensitive structure104. The reflective structure 122 may, therefore, reduce or eliminateradiation-based performance degradation of the semiconductor devicestructure 100 and in a semiconductor device including the semiconductordevice structure 100.

Accordingly, a method of forming a semiconductor device structurecomprises forming at least one reflective structure configured toselectively reflect radiation having a wavelength within a range of fromabout 200 nm to about 400 nm over at least one material of asemiconductor device structure, and exposing the at least one reflectivestructure to radiation having a wavelength within a range of from about200 nm to about 400 nm.

Although FIG. 1B depicts an embodiment of the disclosure where the atleast one reflective structure 122 includes a single pair of thedielectric material 122 a and the another dielectric material 122 b, itwill be readily apparent to one of ordinary skill in the art that the atleast one reflective structure 122 may be formed and configureddifferently. By way of non-limiting example and as described in furtherdetail below, FIGS. 2 through 4 illustrate additional embodiments of thedisclosure.

Referring to FIG. 2, in additional embodiments, a method of forming asemiconductor device structure 200 includes forming at least onereflective structure 222 including a plurality of pairs of a dielectricmaterial 222 a and another dielectric material 222 b. Put another way,the dielectric material 222 a and the another dielectric material 222 bmay be formed and configured to alternate and periodically repeatthroughout a thickness of the reflective structure 222. The dielectricmaterial 222 a and the another dielectric material 222 b may alternateand repeat a desired number of times. For example, the plurality ofpairs of the dielectric material 222 a and the another dielectricmaterial 222 b may be periodically repeated in accordance with Equation1 above to achieve a desired reflectivity of the reflective structure222. The dielectric material 222 a and the another dielectric material222 b may be repeated an equal number of times (e.g., such that thereflective structure 222 has an odd number of adjacent dielectricmaterial interfaces), or one of the dielectric material 222 a and theanother dielectric material 222 b may be repeated one more time than theother (e.g., such that the reflective structure 222 has an even numberof adjacent dielectric material interfaces). The dielectric material 222a and another dielectric material 222 b may be substantially similar tothe dielectric material 122 a and the another dielectric material 122 bpreviously described with respect to FIG. 1B. The reflective structure222 may be formed using conventional processes such as PVD, CVD, or ALD,which are not described in detail herein. In addition, after forming thereflective structure 222, the semiconductor device structure 200 may besubjected to additional processing (e.g., at least one plasma treatmentprocess), such as that previously described in relation to thesemiconductor device structure 100.

Referring to FIG. 3, in further embodiments, a method of forming asemiconductor device structure 300 includes forming at least onereflective structure 322 including a single sequence or an at leastpartially repeating sequence of at least three different dielectricmaterials. As a non-limiting example, as depicted in FIG. 3, thereflective structure 322 may be formed and configured to include adielectric material 322 a on or over at least the radiation-sensitivestructure 104, another dielectric material 322 b on the dielectricmaterial 322 a, and an additional dielectric material 322 c on theanother dielectric material 322 b. A refractive index contrast betweenone pair of adjacent dielectric materials of the reflective structure322 (e.g., between the dielectric material 322 a and the anotherdielectric material 322 b) may be different than a refractive indexcontrast between another pair of adjacent dielectric materials of thereflective structure 322 (e.g., between the another dielectric material322 b and the additional dielectric material 322 c). Thus, differentpairs of adjacent dielectric materials may be formed to reflectradiation within different wavelength ranges. Reflecting radiationwithin the different wavelength ranges may, for example, promote thereflection of a particular radiation wavelength or range of radiationwavelengths (e.g., wavelength(s) within an overlapping portion of thedifferent wavelength ranges). Alternatively, a refractive index contrastbetween one pair of adjacent dielectric materials of the reflectivestructure 322 (e.g., between the dielectric material 322 a and theanother dielectric material 322 b) may be the same as a refractive indexcontrast between another pair of adjacent dielectric materials of thereflective structure 322 (e.g., between the another dielectric material322 b and the additional dielectric material 322 c). Thus, differentpairs of adjacent dielectric materials may be formed and configured toreflect radiation within a single wavelength range. The reflectivestructure 322 may be formed using conventional processes such as PVD,CVD, or ALD, which are not described in detail herein. In addition,after forming the reflective structure 322, the semiconductor devicestructure 300 may be subjected to additional processing (e.g., at leastone plasma treatment process), such as that previously described inrelation to the semiconductor device structure 100.

Referring to FIG. 4, in yet further embodiments, a method of forming asemiconductor device structure 400 includes forming a plurality ofreflective structures 424 on or over at least the radiation-sensitivematerial 104. For example, as depicted in FIG. 4, the reflectivestructure 122 may be formed on or over the radiation-sensitive material104, and another reflective structure 426 may be formed on or over thereflective structure 122. The another reflective structure 426 mayinclude a single sequence or an at least partially repeating sequence ofat least two dielectric materials having different refractive indices.For example, as illustrated in FIG. 4, the another reflective structure426 may include a first dielectric material 426 a formed on or over thereflective structure 122, and a second dielectric material 426 b formedon the first dielectric material 426 a. A refractive index contrastbetween at least one pair of adjacent dielectric materials of theanother reflective structure 426 (e.g., between the first dielectricmaterial 426 a and the second dielectric material 426 b) may bedifferent than a refractive index contrast between at least one pair ofadjacent dielectric materials of the reflective structure 122 (e.g.,between the dielectric material 122 a and the another dielectricmaterial 122 b). In addition, if the another reflective structure 426 isformed on the reflective structure 122, a refractive index contrastbetween adjacent dielectric materials of the another reflectivestructure 426 and the reflective structure 122 (e.g., between the firstdielectric material 426 a and the another dielectric material 122 b) maybe different than a refractive index contrast between one or more of atleast one pair of adjacent dielectric materials of the reflectivestructure 122 (e.g., between the dielectric material 122 a and theanother dielectric material 122 b) and at least one pair of adjacentdielectric materials of the another reflective structure 426 (e.g.,between the first dielectric material 426 a and the second dielectricmaterial 426 b). Thus, the plurality of reflective structures 424 may beformed and configured to reflect radiation within multiple wavelengthranges. In further embodiments, a refractive index contrast of at leasttwo of a pair of adjacent dielectric materials of the reflectivestructure 122, a pair of adjacent dielectric materials of the anotherreflective structure 426, and adjacent dielectric materials of thereflective structure 122 and the another reflective structure 426 may bethe same. Thus, some different pairs of adjacent dielectric materials ofthe plurality of reflective structures 424 may be formed and configuredto reflect radiation within a single wavelength range. In addition, eachreflective structure (e.g., the reflective structure 122, and theanother reflective structure 426) of the plurality of reflectivestructures 424 may be formed and configured to exhibit the samereflectivity, or at least one of the plurality of reflective structures424 may be formed and configured to exhibit a different reflectivitythan at least one other of the plurality of reflective structures 424.The plurality of reflective structures 424 may be formed usingconventional processes such as PVD, CVD, or ALD, which are not describedin detail herein. Further, after forming the plurality of reflectivestructures 424, the semiconductor device structure 400 may be subjectedto additional processing (e.g., at least one plasma treatment process),such as that previously described in relation to the semiconductordevice structure 100.

The methods and structures of the disclosure may improve semiconductordevice (e.g., CMOS device) reliability, performance, and durability ascompared to conventional methods and structures. For example, thereflective structures 122, 222, 322 and the plurality of reflectivestructures 424 described herein reduce radiation-based damage, defects,and impurities to at least one radiation-sensitive structure 104 (e.g.,at least one CMOS transistor) of the semiconductor device structures100, 200, 300, 400. The reflective structures 122, 222, 322 and theplurality of reflective structures 424 contribute minimal changes to thesemiconductor device structures 100, 200, 300, 400 and also do notnecessitate changes to plasma treatment processes used after subsequentformation of the reflective structures 122, 222, 322 and the pluralityof reflective structures 424. The methods and structures of thedisclosure also facilitate the selective transmission of radiation(e.g., wavelengths of radiation outside of the photonic stopband of thereflective structures 122, 222, 322, and the plurality of reflectivestructures 424), enabling the use of various photolithographic processes(e.g., photolithographic processes utilizing 193 nm UV radiation) insubsequent processing of the semiconductor device structures 100, 200,300, 400. In addition, the methods and structures (e.g., the reflectivestructures 122, 222, 322, and the plurality of reflective structures424) of the disclosure may enable the use of radiation-producingprocessing equipment to form semiconductor device structures that wouldat least be more difficult to form using non-radiation-producingprocessing equipment. Furthermore, the methods and structures of thedisclosure may facilitate electrical isolation of structures within thesemiconductor device structures 100, 200, 300, 400.

While embodiments of the disclosure have been described and illustratedwith reference to semiconductor device structures 100, 200, 300, 400that include transistors, such as in a CMOS device, the methods andreflective structures 122, 222, 322 and the plurality of reflectivestructures 424 of the disclosure may be used in other semiconductordevices in which protection of radiation-sensitive structures isdesired. The reflective structures 122, 222, 322 and the plurality ofreflective structures 424 of the disclosure may also be positioned indifferent locations on the semiconductor devices.

While the disclosure is susceptible to various modifications andalternative forms, specific embodiments have been shown by way ofexample in the drawings and have been described in detail herein.However, the disclosure is not intended to be limited to the particularforms disclosed. Rather, the disclosure is to cover all modifications,equivalents, and alternatives falling within the scope of the disclosureas defined by the following appended claims and their legal equivalents.For example, elements and features disclosed in relation to oneembodiment may be combined with elements and features disclosed inrelation to other embodiments of the disclosure.

1. A semiconductor device structure, comprising: at least one structureon a substrate; and a distributed Bragg reflector comprising at leastthree dielectric materials having different refractive indices than oneanother over the at least one structure, the distributed Bragg reflectorconfigured to selectively reflect greater than or equal to about 60percent of radiation within a wavelength range of from about 200 nm toabout 400 nm.
 2. The semiconductor device structure of claim 1, whereinthe at least one structure comprises at least one transistor. 3.(canceled)
 4. The semiconductor device structure of claim 1, furthercomprising at least one additional distributed Bragg reflector over thedistributed Bragg reflector.
 5. The semiconductor device structure ofclaim 4, wherein a refractive index contrast between at least twoadjacent dielectric materials of the at least one additional distributedBragg reflector is different than a refractive index contrast between atleast two adjacent dielectric materials of the distributed Braggreflector.
 6. A semiconductor device structure, comprising: aradiation-sensitive structure; a first distributed Bragg reflectorcomprising a first pair of adjacent dielectric materials over theradiation-sensitive structure and configured to substantially reflect UVradiation within a selected wavelength range and to substantially allowtransmission of UV radiation outside of the selected wavelength range;and a second distributed Bragg reflector on the first distributed Braggreflector and comprising a second pair of adjacent dielectric materialshaving a different refractive index contrast than the first pair ofadjacent dielectric materials, the second distributed Bragg reflectorconfigured to substantially reflect UV radiation within the selectedwavelength range and to substantially allow transmission of UV radiationoutside of the selected wavelength range.
 7. The semiconductor devicestructure of claim 6, wherein the UV radiation outside of the selectedwavelength range comprises one or more wavelengths below the selectedwavelength range.
 8. The semiconductor device structure of claim 6,wherein the selected wavelength range is from about 200 nm to about 400nm.
 9. The semiconductor device structure of claim 8, wherein the UVradiation outside of the selected wavelength range has a wavelength ofabout 193 nm.
 10. The semiconductor device structure of claim 6, whereinthe first pair of adjacent dielectric materials comprises: a firstdielectric material having a different refractive index less than orequal to about 2.0; and a second dielectric material on the firstdielectric material and having a refractive index greater than or equalto about 2.0.
 11. The semiconductor device structure of claim 10,wherein the first dielectric material is selected from the groupconsisting of SiO₂, Si₃N₄, TiO₂, ZrO₂, HfO₂, Ta₂O₅, and MgO.
 12. Thesemiconductor device structure of claim 11, wherein the seconddielectric material is selected from the group consisting of SiO₂,Si₃N₄, TiO₂, ZrO₂, HfO₂, Ta₂O₅, and MgO.
 13. The semiconductor devicestructure of claim 1, wherein each of the at least three dielectricmaterials is independently selected from the group consisting of SiO₂,Si₃N₄, ZrO₂, HfO₂, TiO₂, Ta₂O₅, MgO, a Group III-V compound, and a GroupII-IV compound.
 14. The semiconductor device structure of claim 1,wherein at least one of the at three dielectric materials exhibits adifferent thickness than at least one other of the at three dielectricmaterials.
 15. The semiconductor device structure of claim 1, wherein arefractive index contrast between a pair of adjacent dielectricmaterials of the at least three dielectric materials is different thananother refractive index contrast between another pair of adjacentdielectric materials of the at least three dielectric materials.
 16. Thesemiconductor device structure of claim 1, wherein the at least onestructure comprises: a gate structure of a transistor; and anelectrically insulative material laterally surrounding the gatestructure.
 17. The semiconductor device structure of claim 16, whereinthe distributed Bragg reflector is located on an upper surface of thegate structure and on an upper surface of the electrically insulativematerial.
 18. A semiconductor device structure, comprising a distributedBragg reflector on an electrically insulative material of a gatestructure of a transistor, the distributed Bragg reflector comprisingdifferent, adjacent dielectric materials independently selected from thegroup consisting of SiO₂, Si₃N₄, ZrO₂, HfO₂, Ta₂O₅, MgO, Group III-Vcompounds, and Group II-IV compounds.
 19. The semiconductor devicestructure of claim 18, wherein the distributed Bragg reflector comprisesSiO₂ vertically adjacent Si₃N₄.
 20. The semiconductor device structureof claim 18, wherein at least one of the different, adjacent dielectricmaterials exhibits a different thickness than at least one other of thedifferent, adjacent dielectric materials.
 21. The semiconductor devicestructure of claim 18, further comprising another distributed Braggreflector on the distributed Bragg reflector.